Ulnar impaction syndrome is a condition in which the ulna bone is too long in relation to the radius bone resulting in impaction of the carpal bones in the wrist. The impacted carpal bones and impinged soft tissues can cause pain and swelling while limiting the range of motion in the wrist. The long term effects of ulnar impaction syndrome can include ligament attenuation and tearing resulting in chronic pain, carpal instability, and permanent arthritis due to the deterioration of the cartilage between the ulna and the carpal bones. To mitigate the symptoms and preclude long-term effects, the ulna can be shortened to a length that corresponds to the length of the radius, thereby reducing or eliminating the impaction on the carpal bones.
Surgically shortening the ulna is typically performed by two cuts made perpendicular to the axis of the ulna to remove the length of bone that the ulna is desired to be shortened by. The two bone segments that remain are then compressed and joined by plates and screws. This method reveals several disadvantages. The first disadvantage is that the relatively small surface area over which the union must occur, which magnifies the effect of any discontinuity or anomaly in the union. These anomalies may result in incomplete healing or nonunion that is susceptible to breakage. Another disadvantage of using this technique is that there is very little room for error when removing the section of bone and removing too much could result in an ulna that is too short. A third disadvantage resulting from using this technique is the plate that is required to hold the bone sections together may be uncomfortable for the patient and may require removal of the plate after the bone has healed, which may be costly, inconvenient, and subjects the patient to the risks of another surgery and anesthesia.
Another method for shortening the ulna involves a diagonal or oblique cut across the ulna. This method is outlined in U.S. Pat. No. 6,689,139 and while it may mitigate the disadvantages of the previously mentioned method, the diagonal cut may introduce other disadvantages when shortening the ulna. The '139 patent discloses a guide that mounts to the ulna and provides a diagonal surface along which a surgeon may sever the ulna. The ulna is then shortened by sliding the opposing sides of the angled cut relative to each other. Since the oblique cuts tend to overlap in compression, there is a risk of bony prominence. The bony prominence may be a source of discomfort for the patient and require further surgery. Another disadvantage that may result from using a diagonal cut to shorten the ulna is that over compression may cause the ulna to be inappropriately shortened too much. A third disadvantage of using the device of the '139 patent is that, during surgery, the bone typically must be held securely in place by the surgeon or some other mechanism while screws are inserted across the diagonal cut.
Therefore, a need exists for a device to aid in performing a shortening osteotomy that overcomes the disadvantages of the aforementioned techniques and is relatively simple to use. In addition, there is a need for a device that facilitates bone healing following a shortening osteotomy.